Here is a quick model I constructed with LEGO just to show how the whole mechanism works. its big, bulky and constrained by the dimensions of lego and peices on hand, but you get the idea.
If that doesnt work, link HERE
I hope to use the lego worm gear, as it is pretty sturdy. All the other gears / arms will be done on the lasercutter [hopefully] and will be a much more compact / efficient unit. there will also be four, perhaps six arms - as many as I can fit onto the worm gear...
Sunday, November 19, 2006
Friday, November 17, 2006
Things are looking up.
In keeping with the idea of the permeable surface transforming into the solid surface, and then applying my new thoughts on motors v. solenoids and those strange re-occuring birds, a strange idea developed.
By suspending the mechanisms - without a supporting framework, that sense of "shutters" is lost. The mechanisms dangle and drift about according to local air currents. When the mechanisms are activated, they begin to open and interact with eachother. Once they are fully open, the loose arangement dissapears and the mechainisms force themselves into a rigid matrix based on the geometry of the individual peices - very simmilar to a crystalization process.
What triggers the mechanisms is particulairly intresting...
As the interaction of the individual mechanisms when triggered is important, perhaps the relaxed state can also influence the actions of the installation. Following the idea of air currents, using strands [switches] within the suspended parts that jostle about and switch the mechanisms on and off - check out Gorretti's blog to see some of these strands at work with her lighting circuits. Once the mechanism is fully open however, connections or switches on the rigid mechanism would interact with the same switches on another rigid mechanism and engage a closing sequence.
The effect would be a surface that is constantly opening and closing [almost breathing] through a combination of air currents and interaction of parts.
I recognise this as an incredibly complex undertaking - most definitly something to be accomplished after christmas, but I feel it is important to project possiblilites. In the immediate future, I would like to create a few working mechanisms, with a much simpler sensor input for the time being. This involves finding motors / suitable worm gears, and then some intensive time on the laser cutter.
By suspending the mechanisms - without a supporting framework, that sense of "shutters" is lost. The mechanisms dangle and drift about according to local air currents. When the mechanisms are activated, they begin to open and interact with eachother. Once they are fully open, the loose arangement dissapears and the mechainisms force themselves into a rigid matrix based on the geometry of the individual peices - very simmilar to a crystalization process.
What triggers the mechanisms is particulairly intresting...
As the interaction of the individual mechanisms when triggered is important, perhaps the relaxed state can also influence the actions of the installation. Following the idea of air currents, using strands [switches] within the suspended parts that jostle about and switch the mechanisms on and off - check out Gorretti's blog to see some of these strands at work with her lighting circuits. Once the mechanism is fully open however, connections or switches on the rigid mechanism would interact with the same switches on another rigid mechanism and engage a closing sequence.
The effect would be a surface that is constantly opening and closing [almost breathing] through a combination of air currents and interaction of parts.
I recognise this as an incredibly complex undertaking - most definitly something to be accomplished after christmas, but I feel it is important to project possiblilites. In the immediate future, I would like to create a few working mechanisms, with a much simpler sensor input for the time being. This involves finding motors / suitable worm gears, and then some intensive time on the laser cutter.
Avian Tendencies
After some consideration and deliberation, I've decided that the previous idea was not alltogether unlike a very comlicated set of shutters, and could use a bit more imagination and fun.
First off, solenoids are proving to be quite difficult. They are bulky, have a considerable power requirement, have only on / off states, and cannot stay in the on position for extended periods of time lest they overheat [some issues with my More Power! statement from earlier...] A much more elegant solution is one involving geared motors linked to the mechanism.
It avoids any sort of compound lever systems (+), allows the mechanism to operate at a number of positions as opposed to on / off (+), lighter - with a reduced power demand (+), doesn't make that cool "snick!" sound of solenoids ( - ). A compromise then.
When drawing this, the image of birds kept popping into my head. This linked with overcoming the shutters led to a whole new idea...
First off, solenoids are proving to be quite difficult. They are bulky, have a considerable power requirement, have only on / off states, and cannot stay in the on position for extended periods of time lest they overheat [some issues with my More Power! statement from earlier...] A much more elegant solution is one involving geared motors linked to the mechanism.
It avoids any sort of compound lever systems (+), allows the mechanism to operate at a number of positions as opposed to on / off (+), lighter - with a reduced power demand (+), doesn't make that cool "snick!" sound of solenoids ( - ). A compromise then.
When drawing this, the image of birds kept popping into my head. This linked with overcoming the shutters led to a whole new idea...
First Steps
After finding that "seed crystal" of an idea, I began to develop a body of work that would support it. This began with analog drafting, but I soon realized that there was far more tuning of the geometry of the mechanism required. To accomplish this I moved into the digital realm and started mucking about in AutoCAD, developing a relationship between radii and axis of rotations within the mechanism. This got increasingly complicated, and I eventually scaled back to a very simple itteration that I was determined to test.
To do this, I first developed a geometry suited for the open-box solenoid [pictured in the middle] and created a file for the laser-cutter [getting cut friday morning with any luck]. I then went and got a tube solenoid, with a greater throw - as the distance the solenoid traveled was a serious constraint in developing geometry. The tube solenoid required some serious modifications - the mounting frame was cut off and ground smooth, and the spring was shortened to reduce the amount of force required to active it. The open box solenoid works well off a 9V battery, however the tube still requires a full 12V with plenty of current - so there's some work ahead to make things operate effectively and efficiently. I also created a few [shoddy] renderings to help communicate my idea.
These renderings depict a few open mechanisms placed on a supporting grid, and some of the light blocking / diffusing possibilites. While working with the issue of shade and shadow - I created a comparator circuit using some of the 741 operational amplifiers and a photoresistor that would register the difference between light and dark and then trigger the solenoid - esssentially keying the mechanism to fire when in shadow eg. when someone walks in between it and a light source.
The circuit works...ish. It responds to light and dark - however, even using 18Vs, the circuitry consumes too much power and the solenoid response is sluggish and weak - presumably too weak to operate the mechanism. I am not entirely certain of this, as I will be building a test-run of the mechanism once I get the lasercutting done, but things aren't looking too good. I need more Power!
To do this, I first developed a geometry suited for the open-box solenoid [pictured in the middle] and created a file for the laser-cutter [getting cut friday morning with any luck]. I then went and got a tube solenoid, with a greater throw - as the distance the solenoid traveled was a serious constraint in developing geometry. The tube solenoid required some serious modifications - the mounting frame was cut off and ground smooth, and the spring was shortened to reduce the amount of force required to active it. The open box solenoid works well off a 9V battery, however the tube still requires a full 12V with plenty of current - so there's some work ahead to make things operate effectively and efficiently. I also created a few [shoddy] renderings to help communicate my idea.
These renderings depict a few open mechanisms placed on a supporting grid, and some of the light blocking / diffusing possibilites. While working with the issue of shade and shadow - I created a comparator circuit using some of the 741 operational amplifiers and a photoresistor that would register the difference between light and dark and then trigger the solenoid - esssentially keying the mechanism to fire when in shadow eg. when someone walks in between it and a light source.
The circuit works...ish. It responds to light and dark - however, even using 18Vs, the circuitry consumes too much power and the solenoid response is sluggish and weak - presumably too weak to operate the mechanism. I am not entirely certain of this, as I will be building a test-run of the mechanism once I get the lasercutting done, but things aren't looking too good. I need more Power!
New Direction
Continuing with the idea of responsive building skins carried forward from Montreal and in light of the research of the past few weeks I've set off in a some semblance of a direction.
Bare bones, here it is:
Using the skin of a building [I'm using the term building loosely here, its simply the most fitting analogy] to inform the building of its environment, and then having the building respond to the data to tune itself to that environment.
An awfully difficult difficult program when you get into it, because it means designing both a skin condition, and a structure that responds to / alters this skin condition.
To begin, I am starting small, and making a structure that changes its shape based on information gathered by the environment.
Here are some of the early ideas:
The elements can be positioned in any orientation; wall, roof, whatever. The solid surface can then react with different elements in an environment and have very different effects on the contained environment - sun, precipitation, wind, privacy, etc etc. The sensor input is equally open-ended as it is inherently linked.
Bare bones, here it is:
Using the skin of a building [I'm using the term building loosely here, its simply the most fitting analogy] to inform the building of its environment, and then having the building respond to the data to tune itself to that environment.
An awfully difficult difficult program when you get into it, because it means designing both a skin condition, and a structure that responds to / alters this skin condition.
To begin, I am starting small, and making a structure that changes its shape based on information gathered by the environment.
Here are some of the early ideas:
The elements can be positioned in any orientation; wall, roof, whatever. The solid surface can then react with different elements in an environment and have very different effects on the contained environment - sun, precipitation, wind, privacy, etc etc. The sensor input is equally open-ended as it is inherently linked.
Research Directions
Following Montreal, we each returned to our original research and began to investigate further. My intentions seemed to lead away from my original inventor Faraday. After some deliberation, I focused on Luigi Galvani. His research proved to be far more intruiging - as he wasn't entirely certain what he was dealing with and his experiments concerning bioelectricity and the relationship between physical movement and electric signals was much more alligned with my intrests.
In the course of my research of Galvani, two significant phenomenon emerged: chronobiology and biofeedback. Cronobiology is the study of the natural cycles within organisms - circadian rythms, menstrual cycles, migration patters, etc etc. This is particulairly intresting because it deals with an organisms responses to pressures / forces in thier immediate environment.
Biofeedback is the process in which an individual gains information about their biological functions - blood pressure, body temperature, muscle tension, etc etc - and then attempts to alter these processes using perscribed exercises, gauging the bodys response using the aformentioned sensors. Biofeedback has significant medicinal uses ranging from stress reduction to prosthetics [shown below]. It is of intrest to note that nearly all of these sensors deal directly with the surface of the skin, tapping into such things as temperature, conductance created by sweat, and electrical impulses generated by muscles moving underneath the skins surface.
The prosthetics are of particular intrests, as myoelectric control directly links electrical impulses with muscle movement - artificial movement generate from the body's contained electrical energies. When this relationship between electrical impulses and produced mechanical movementis applied to the musculo-skeletal structure of the human body, things become particulairly intresting...
In the course of my research of Galvani, two significant phenomenon emerged: chronobiology and biofeedback. Cronobiology is the study of the natural cycles within organisms - circadian rythms, menstrual cycles, migration patters, etc etc. This is particulairly intresting because it deals with an organisms responses to pressures / forces in thier immediate environment.Biofeedback is the process in which an individual gains information about their biological functions - blood pressure, body temperature, muscle tension, etc etc - and then attempts to alter these processes using perscribed exercises, gauging the bodys response using the aformentioned sensors. Biofeedback has significant medicinal uses ranging from stress reduction to prosthetics [shown below]. It is of intrest to note that nearly all of these sensors deal directly with the surface of the skin, tapping into such things as temperature, conductance created by sweat, and electrical impulses generated by muscles moving underneath the skins surface.
The prosthetics are of particular intrests, as myoelectric control directly links electrical impulses with muscle movement - artificial movement generate from the body's contained electrical energies. When this relationship between electrical impulses and produced mechanical movementis applied to the musculo-skeletal structure of the human body, things become particulairly intresting...
Tuesday, November 07, 2006
Air Pressure Switch Info
[originally posted on the pHnAeCuK blog @ www.pneuhack.blogspot.com]
Here's Just a little follow up info on those air-pressure switches:
They are two keyboard contacts placed together - the activation pressure can be tuned to suit its application, Kai and I experimented with both the seperator material (distance between) the contacts, and the size of the "nubbin" that concentrates the pressure on the contacts themselves. With no seperator, the nubbin can be smaller than a grain of sand - the activation pressure is incredibly small : simply blowing on the swicth would activate it, or the weight of a zip-lock bag would trigger it. If held stationary, the slightest pressure on the bag would again cause the switch to activate.
As it is, we could mount the switch between the inner and outer membranes, it is paper thin and adheres with tape. any pressure to the membrane (touch) or an increase in internal air pressure (bending of the tube) would activate it.
The other option is modifying the switch (a relatively thick seperator material and a larger nubbin) and placing it closer to the bottom of a tube - this will require some serious tuning to get it to respond to air pressure changes created by bending a tube, but is still possible.
Another good thing are the switches are very easy to make (takes some precision, but with enough people on it (2-3) we can have them built and installed for about 2 minutes a switch. AND they are ridiculously cheap - salvaged contacts, a little tape and some strips of wire - so no real cost.
Here's Just a little follow up info on those air-pressure switches:
They are two keyboard contacts placed together - the activation pressure can be tuned to suit its application, Kai and I experimented with both the seperator material (distance between) the contacts, and the size of the "nubbin" that concentrates the pressure on the contacts themselves. With no seperator, the nubbin can be smaller than a grain of sand - the activation pressure is incredibly small : simply blowing on the swicth would activate it, or the weight of a zip-lock bag would trigger it. If held stationary, the slightest pressure on the bag would again cause the switch to activate.
As it is, we could mount the switch between the inner and outer membranes, it is paper thin and adheres with tape. any pressure to the membrane (touch) or an increase in internal air pressure (bending of the tube) would activate it.
The other option is modifying the switch (a relatively thick seperator material and a larger nubbin) and placing it closer to the bottom of a tube - this will require some serious tuning to get it to respond to air pressure changes created by bending a tube, but is still possible.
Another good thing are the switches are very easy to make (takes some precision, but with enough people on it (2-3) we can have them built and installed for about 2 minutes a switch. AND they are ridiculously cheap - salvaged contacts, a little tape and some strips of wire - so no real cost.
Montreal Part Deux
See what I did there? tossed in a bit of french without even thinking about it.
Moving on...
Fitting the pneumatic tubes with electronics proved to be more difficult than anticipated. Our trial runs with taping the sensors to the tubes worked well, but was a little fragile, especially if people were rubbing up against them as they penetrated the structure. To solve this, we needed to cover the sensors in a manner that protected them while still allowing them to function effectively. After various trials, we taped the sensors to a collar constructed of the tubing that slid over the tubes.
This was effective initially, however, using a collar provided a constant air pressure that meant that when constricted, all sensors would fire at once, or one would close and negate any input from other sensors on the same tube. In addition to this, a variance in air pressures meant that each sensor needed to be calibrated...
The environmental sensors were actually contact sensors, made from the electrical contacts canibalized from old keyboards. The distance between the two contacts, and the area of pressure that acts on the sensor are the two major variables that allow you to tune the sensor. We needed a few of these buggers so we had a sensor building party! Jeff Palistch from RPI then spent a late night trying to configure the sensors and collars accompanied by some boreal, a local micro brew.
Detuning the sensors to the point where they were no longer triggered by changes in air pressure not only solved the "input overlap" but cut the time requirements considerably. the sensors would only respond to people brushing against them when they penetrated the ring, or a very strong increase in air pressure - like when someone hugged a tube.
These sensors were then wired to act as a switch for some hacked LED toys from the local dollar store. These toys resembled Lightsabres, and would change the pattern of the contined flashing leds each time the switch was closed. This was not quite the delay circuits we were originally intending, however they were far less expensive, pre-constructed, and stil retained the ability to provide some sort of recognition of passage / interaction with the structure. We also ran into a wire shortage, meaning that these lightsabres would need to be wired with close proximity to the sensors in a parallel circuit, so into the collar they went.
At this point Drew and Rachel came in with some very cool hacked personal security alarms which were then wired to a photo resistor taped to the LEDs, and the output was sent to a mixer / amp which produced some intresting / odd / awesome sounds. When multiple signals from these alarms interacted on their way to the mixer, the interference produced even odder sound, all based on the pattern of the flashing LED. Kai's car was also functioning, however, detuning of the sensors meant that the feedback loop was realized.
All in all, I think we accomplished a pretty intresting peice of work. The collaberation with members of RPI was fantastic and the location couldn't have been better. Thanks to all our team members, Concordia university, Patrick and Ted.
Moving on...
Fitting the pneumatic tubes with electronics proved to be more difficult than anticipated. Our trial runs with taping the sensors to the tubes worked well, but was a little fragile, especially if people were rubbing up against them as they penetrated the structure. To solve this, we needed to cover the sensors in a manner that protected them while still allowing them to function effectively. After various trials, we taped the sensors to a collar constructed of the tubing that slid over the tubes.
This was effective initially, however, using a collar provided a constant air pressure that meant that when constricted, all sensors would fire at once, or one would close and negate any input from other sensors on the same tube. In addition to this, a variance in air pressures meant that each sensor needed to be calibrated...
The environmental sensors were actually contact sensors, made from the electrical contacts canibalized from old keyboards. The distance between the two contacts, and the area of pressure that acts on the sensor are the two major variables that allow you to tune the sensor. We needed a few of these buggers so we had a sensor building party! Jeff Palistch from RPI then spent a late night trying to configure the sensors and collars accompanied by some boreal, a local micro brew.
Detuning the sensors to the point where they were no longer triggered by changes in air pressure not only solved the "input overlap" but cut the time requirements considerably. the sensors would only respond to people brushing against them when they penetrated the ring, or a very strong increase in air pressure - like when someone hugged a tube.
These sensors were then wired to act as a switch for some hacked LED toys from the local dollar store. These toys resembled Lightsabres, and would change the pattern of the contined flashing leds each time the switch was closed. This was not quite the delay circuits we were originally intending, however they were far less expensive, pre-constructed, and stil retained the ability to provide some sort of recognition of passage / interaction with the structure. We also ran into a wire shortage, meaning that these lightsabres would need to be wired with close proximity to the sensors in a parallel circuit, so into the collar they went.
At this point Drew and Rachel came in with some very cool hacked personal security alarms which were then wired to a photo resistor taped to the LEDs, and the output was sent to a mixer / amp which produced some intresting / odd / awesome sounds. When multiple signals from these alarms interacted on their way to the mixer, the interference produced even odder sound, all based on the pattern of the flashing LED. Kai's car was also functioning, however, detuning of the sensors meant that the feedback loop was realized.
All in all, I think we accomplished a pretty intresting peice of work. The collaberation with members of RPI was fantastic and the location couldn't have been better. Thanks to all our team members, Concordia university, Patrick and Ted.
Montreal / Hexagram
You would think that after an epic marathon 2500 kilometer drive across the Canadian shield [in a Hyundai no less], a whirlwind tour of Ottawa, a new baby [and accompanying adventures... congrats to Darcy and Tanya and baby Petter] and exploring Montreal, that one could call it a successful trip and be done with it. This was only the adventure leading up to our hexagram adventures.
Our team: Kai Chang, Rachel Tennenhouse, Andrew Workman and myself, came to hexagram with a minimal understanding of what our collaborators from RPI had created in terms of a pneumatic structure in which we were supposed to embed / integrate our electronic devices. Up to that point, the only communication we had was a few teleconference calls fraught with technical difficulties and PDFs. Kai and I had worked late the nights before our driving to devise an environmental sensor that would work with inputs from human and pneumatic interaction. I'll import the posts from the pHnAeCuK blog for some illumination on these. Beyond that, we had only raw materials and some possible ideas with which to work with.
After much discussion and brainstorming, we decided to attempt to create a feedback loop that consisted of optical, acoustic, and physical triggers and responses. The loop / system was to be initiated by the environmental sensors that would respond to contact and changes in air pressure of the upright tubes. These would in turn send signals to the acoustic circuit - which would interpret / modify / emit the signal which would then in turn be sent to a acoustically triggered car. After being triggered by the sound, the car would move about on a tether attached to the structure. This movement of the structure would in turn cause the structure to deform and cause the tubes to jostle eachother, again triggering the environmental sensors and perpetuating the cycle.
Before we could set about any of these tasks, we first had to refine the pneumatic structure. Our major concern was air loss, as an array of leak points in the system meant we required a much greater air [ and louder - acoustic interference ] air supply. This also effected inflation times and structural rigidity. The main points of loss were the end seams of the tubes and where the tube attached to the PVC framework that served as its air supply. Each tube was constructed out of a solid cylinder / tube of 3mil polyethylene plastic bagging - sort of like the roll of bagging found for supermarket produce bags, but bigger and stronger. These were then welded with a single simple seam a la heat gun and pressure, and attached to the PVC frame /air supply with elastic bands.
My solution to these issues was twofold: For the welded seams at the top, there was a serious weakness in the actual sealing system. By folding the material over successive series of welds produced both a better seal, and meant that the force created by the air pressure was applied to the material itself, instead of applying tensional stress to the welded seam.
To solve the air leakage at the frame, Kai and I needed to make a trip to the local Canadian tire [about 10 blocks away, and POURING rain each time we had to go]. The seal was constructed out of automotive heater hose, ATV UltraBlack gasket maker / sealant, and some gear / screw clamps. The heater hose's purpose was to both increase the circumference [surface area] that the tube would contact with - meaning the tube could sit flatter with a minimal series of folds that air could escape through, and to provide a softer material for the clamp to sink into and improve the seal. The ATV went in between the heater hose and the PVC, sealing the connection and affixing the assembly to the frame. ATV should have been applied between the tubes and the heater hose, however we were constantly taking the tubes on and off, so this would have gotten rather messy.
I hope to get some drawings finished that will hopefully provide some clarity to all this. Ill put them up when I can. Anyways, the system was incredibly successful - the overall system still lost a little air through the vacuum and pinpoint holes, but our test bags held air at incredible pressures for sustained periods. In addition to max pressures from the compressors [about 100 psi], it even survived getting ridden rodeo style by Kai. I wish I had pictures of this, but honestly I was laughing too hard.
With the pneumatic system effectively functional, we shifted to electronics.
This is getting a little long here, so I'll continue this in the next entry.
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